1. Field of the Invention
This invention relates to a lock assembly for a slide fastener and more particularly to such a lock assembly which is capable of releasably locking a slider on a slide fastener attached to a garment article.
2. Prior Art
There are known many lock devices of this character, an example of which is disclosed in Japanese Utility Model Publication No. 33-13798 and which comprises an engaging pin formed in the lower surface of a slider pull tab and vertically projecting so as to enter through the upper surface of a lock into hooked engagement with the latter. A disadvantage of this prior art device is that since it is located on the back of the pull tab, the engaging pin cannot be viewed from outside and hence is extremely cumbersome to fit with the lock. Another drawback of the device is found in that the pull tab and the lock when joined together form a junction so stiff and hard as to prohibit their relative movement which is urged by bending stresses applied in different directions especially with the slide fastener attached to a flexible garment article such as bags or similar containers, with the results that the engaging parts of the device receive localized strains and become susceptible to wear and damage.
Another prior art device is disclosed in Japanese Utility Model Laid-Open Publication No. 62-115476 in which a slider pull tab having an engaging aperture is arranged to enter through an opening in the front end of a lock having a locking prong engageable in the engaging aperture of the pull tab. Such device has a drawback in that it is quite tedious to have to align the pull tab with the opening of the lock and therefore the user would often leave the pull tab disengaged from the lock when he thinks it unnecessary to completely lock the slide fastener on a bag or the like, in which instance the bag is apt to open up inadvertently while it is being carried. This prior art device also has the same problem associated with bending stresses as is encountered by the first exemplified prior art.